Method and apparatus for minimizing overhead in a communication system

• US 6,359,877 B1
• Filed: 07/21/1998
• Issued: 03/19/2002
• Est. Priority Date: 07/21/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Khan, Farooq Ullah, Rathonyi, Béla Stefan Kazmir, Olofsson, Håkan Gunnar
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US09/120,163
• Time in Patent Office: 1,337 Days
• Field of Search: 370/391, 370/312, 370/394, 370/399, 370/422, 370/216, 370/320, 370/392, 370/477, 370/242, 370/256, 370/236, 370/471, 370/322, 370/349, 370/221, 370/359, 370/494, 370/232, 370/252, 370/389, 370/395, 710/129, 709/223, 709/228, 709/245, 709/250, 709/224, 709/231, 709/229, 709/233, 709/203, 709/237, 709/239, 725/67, 725/48, 348/423.1, 348/461, 455/427, 455/557, 455/419, 455/424, 386/112, 375/132, 375/222, 375/354, 375/220, 714/748, 714/799, 714/233, 714/794, 714/227, 714/704
• US Class Current: 370/349
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A method and apparatus are provided for minimizing overhead in packet re-transmission in a communication system. Each packet is given a sequence number, based on a current transmission rate, the size of the packet, and a previously assigned sequence number. The packet size can be adapted so that the entire packet fits into a single transmission block. The packet size may also be adapted based on throughput. The packet size may be adapted based on the transmission rate and/or throughput, whether the packet is being transmitted the first time or if it is being re-transmitted. Alternately, if the packet is being re-transmitted, the packet is transmitted at its original transmission rate, regardless of the current transmission rate.

Claims

1. A method for transmitting packets in a communication system, the method comprising the steps of:

determining a current transmission rate;

assigning a sequence number to a packet for transmission based on the current transmission rate, the size of the packet, and a sequence number of a previously transmitted packet; and

transmitting the packet at the current transmission rate.

2. The method of claim 1, further comprising:

adapting a packet size so that the entire packet fits into a single transmission block at the current transmission rate.

3. The method of claim 2, wherein the step of adapting further comprises:

determining whether the packet for transmission is the same size as a packet that can be transmitted in a single transmission block at the current transmission rate; and

if the packet is larger, dividing the packet for transmission into smaller packets.

4. The method of claim 3, further comprising, if the packet for transmission is smaller than a packet that can be transmitted in a single transmission block, adding additional packets in the transmission block.

5. The method of claim 1, further comprising:

receiving a transmitted block including one or more packets;

detecting errors in the one or more packets; and

re-transmitting any of the one or more packets included in the block in which there are detected errors, wherein if, at the time of re-transmission, the transmission rate is lower than the rate at which the packets were originally transmitted, the packet is divided into smaller packets, and the smaller packets are reassigned sequence numbers.

6. The method of claim 5, wherein the step of detecting comprises:

checking the one or more packets of the transmitted block for errors; and

releasing those packets of the transmitted block in which there are no detected errors.

7. The method of claim 5, further comprising a step of adapting a packet size to maximize throughput based on a number of packets re-transmitted during a certain time period.

8. The method of claim 1, further comprising the steps of:

determining whether a packet is being re-transmitted, wherein if the packet is not being re-transmitted, the steps of determining the current transmission rate, assigning a sequence number, and transmitting the packet at the current transmission rate are performed, or if the packet is being re-transmitted, the packet is re-transmitted at its original transmission rate.

9. A transceiver comprising:

a processor for determining a current transmission rate and assigning a sequence number to a packet for transmission based on the current transmission rate, the size of the packet, and a sequence number of a previously transmitted packet; and

a transmitter for transmitting the packet at the current transmission rate.

10. The transceiver of claim 9, wherein the processor adapts the packet size so that the entire packet fits into a single transmission block at the current transmission rate.

11. The transceiver of claim 10, wherein the processor determines whether the packet for transmission is the same size as a packet that can be transmitted in a single transmission block at the current transmission rate, and if the packet is larger, the processor divides the packet for transmission into smaller packets.

12. The transceiver of claim 11, wherein if the packet for transmission is smaller than a packet that can be transmitted in a single transmission block, the processor adds additional packets in the transmission block.

13. The transceiver of claim 9, wherein the transmitted block is received and the processor detects errors in the transmitted block, and if any errors are detected in the transmitted block, the transmitter re-transmits packets in which there are detected errors, and wherein if, at the time of re-transmission, the transmission rate is lower than the rate at which the packets were originally transmitted, the processor divides the packet into smaller packets and reassigns sequence numbers to the smaller packets.

14. The transceiver of claim 13, wherein the processor detects errors by checking packets of the transmitted block for errors and releasing those packets of the transmitted block in which there are no detected errors.

15. The transceiver of claim 14, wherein the processor adapts a packet size to maximize throughput based on a number of packets re-transmitted during a certain time period.

16. The transceiver of claim 9, wherein the processor determines whether a packet is being re-transmitted, and wherein if the packet is not being re-transmitted, the processor determines the current transmission rate and assigns the sequence number and the transmitter transmits the packet, or if the packet is being re-transmitted, the transmitter re-transmits the packet at its original transmission rate.